4-Lined Plant Bug

Posted on June 1st, 2017

stacey tips art 1I saw it with my own eyes… the 4-Lined Plant Bug! This is the quick-moving culprit that is attacking my Montauk Daisy right now.  I was working in the garden and a little too close for this bug’s comfort.  It immediately felt my presence and scattered fast!  This bug looks like it is built for speed.  The adult’s yellowish/green, sleek body is colorfully patterned with 4 black racing stripes.  The nymphs(young stage) tend to be more reddish/orange with black spots on their abdomen. If you have the chance, head out to your garden today and see if you can spot this speedy plant feeder.  Take a look at your herbs; especially mint, basil, lemon verbena, and sage.  No sign of the plant bug there?  Head over to your flowers such as; nepeta, coreopsis, dahlias, morning glory, lupine, geranium, zinnia, and marigolds.  Still no sign? Walk to the woody plant section of your garden and investigate your azalea, dogwood, forsythia, honeysuckle, hydrangea, viburnum, caryopteris, and weigela.  Veggie gardeners, you may even want to look at your lettuce, squash, melons, and cucumbers. Frustrating!  This bug is not too fussy.

The best time to begin your 4-lined plant bug hunt is in May.  The adults lay their banana-shaped eggs in right angles on the top stems of plants in the Fall.  The eggs overwinter and the nymphs begin hatching and feeding usually sometime in May.  They will not show themselves until all of the lush, green foliage on your plants has appeared.  They will wait patiently until your plants are looking their greenest before they attack.  For goodness sake, they need something pretty to feed on!

The nymphs with their reddish bodies and small black wing pads, hatch and immediately begin siphoning out the delicious green chlorophyll from the leaves.  It is kind of like they have their own juicing program.  They inject a toxin into the leaf that helps break it down and make it easier for them to digest.  Their mouths look like little needles or straws.  They pierce the top of the leaf surface and suck out the yummy, green juice.  This feeding action leaves your plants with round, uniform dots on the leaves.  The dots can be very close together.  They look kind of blackish/brown at first and may turn white to clear.  The dots may even fall out, leaving a hole in the leaf.  Usually, the diagnosis for a plant with round, brown dots on the leaf is a fungal leaf spot and often a fungicide is prescribed.  Be careful!  It may be our speedy culprit.  He is swift and likes to hide under the leaf or drop to the ground so you cannot see him, but the round, little dots he leaves behind are a sure sign that he has been there.

The best way to control this “true” bug is to start your spray treatments early on, probably sometime in May, when they first hatch.  In April, begin with Bonide’s All Season Horticultural Oil.  It will do a good job at suffocating the overwintering eggs of the 4-Lined Plant Bug before they hatch. Once those buggers have hatched, it is time to switch to a different product.  In the organic category, Bonide’s Japanese Beetle Killer and Safer’s Insecticidal Soap & End All will do the trick. For something that packs a little more punch, conventional products, such as; Bonide’s Eight & Bayer’s Rose & Flower Insect Killer will really knock them out.

There are other methods that require a little closer inspection but if you have the time and interest, may work for you.  In the Fall, you can inspect the top 2 inches of your garden plants for the banana-shaped eggs of the 4-Lined Plant Bug.  They usually lay them in groups of 6 and at 90-degree angles.  The eggs are kind of easy to spot.  If you see them, you can remove them by hand or prune them off.  Sometimes, a Spring clean-up consisting of a 3-inch shearing off of plants can also do the trick.  I have also heard of planting mint as a “trap crop”.  They like it so much that it may be the only plant they attack, leaving your others alone.

The bottom line is, the 4-Lined Plant Bug does not usually kill your plants, especially large ornamental plants.  They can be more destructive on herbs and veggies and of course, make your ornamental look not-so-pretty.  If you don’t mind brown spearmint leaves in your Mojito or spotted basil leaves in your tomato, basil, mozzarella salad, then you have nothing to worry about.  If you like entertaining your guests with more edible-looking herbs, then an early-timed spray or two may be the right answer for you!

Come see us at Van Wilgen.  We would love to help!